Although Shiba felt quite impatient to attack the Ugador Clan, he didn't insist on attacking immediately.
With his current speed reaching the arid zone wouldn't take too long compared to before, but he knew that Shire needed time to get used to his new power.
They hadn't managed to obtain information from Bea's father, so they weren't sure of the current power of the Ugador Clan.
Shiba was just an ordinary mortal when he had been a slave serving the Ugador Clan, so he just knew that they were too strong, which didn't mean much given Shiba's point of view back then.
Thus, Shire wanted to ensure that he could use his full power before daring to attack. However, getting used to his increase in power needed time.
Shiba and Eini remained living at the academy meanwhile.
Only the three of them would go to the Ugador Clan after Shire finished getting used to his power.